The present invention relates to a gas turbine for cooling moving blades using a refrigerant, a gas turbine apparatus, and a refrigerant collection method for gas turbine moving blades.
The combustion temperature of a gas turbine has a tendency to increase year by year so as to increase the efficiency and particularly the moving blades which are exposed to combustion gas become high in temperature, so that it is necessary to let a refrigerant flow in them and cool them.
As a refrigerant, compressed air extracted from a compressor, vapor generated by exhaust heat of combustion gas or the like is used.
To improve the efficiency of a gas turbine, it is important to collect and use a refrigerant after cooling the moving blades of the turbine in addition to realization of a high combustion temperature. Therefore, the so-called closed circuit cooling structure that the refrigerant flowing path is a closed circuit, for example, as described in Japanese Patent Application Laid-Open 8-14064 is variously proposed.
The big problems of a gas turbine having such a closed circuit cooling structure are the stress due to centrifugal force caused by rotation of the gas turbine and the sealing property of the connection of the refrigerant flow paths installed in the configuration member of the moving blades and turbine rotor.
The reason for that the stress due to centrifugal force caused by rotation of the gas turbine comes into a problem is shown below.
The turbine rotor rotates at a very high speed round the center line of the turbine, so that remarkable stress due to the centrifugal force is generated in the outer periphery. Particularly the wheel has many moving blades in the outer periphery and the operating centrifugal force is extremely large, so that high strength is required. Generally, inside the configuration member of the turbine rotor, the refrigerant flow paths and others are installed and hence the configuration members are not uniform, so that the stress is concentrated at a specific part and there is the possibility that the strength decreases.
An object of the present invention is to provide a gas turbine requiring realization of high efficiency with increased combustion temperature which has high reliability on the stress due to the centrifugal force caused by rotation of the gas turbine and high efficiency.
A gas turbine according to the present invention has a turbine rotor which includes a plurality of moving blades having cooling paths through which a refrigerant flows inside, a plurality of wheels having the aforementioned moving blades in the outer periphery, and at least a spacer member to be installed between the neighboring wheels, wherein the spacer member has a plurality of flow paths through which a refrigerant after cooling the moving blades flows and the plurality of flow paths have the first flow paths interconnecting to the cooling paths installed in the moving blades on the first wheel neighboring with the spacer members and interconnecting to the first space formed on the side wall surface with which the second wheel neighboring with the spacer member and the spacer member is in contact and the second flow paths interconnecting to the cooling paths installed in the moving blades on the second wheel and interconnecting to the second space formed on the side wall surface with which the first wheel and the spacer member are in contact.
Further, a gas turbine apparatus according to the present invention has a turbine rotor which includes a plurality of moving blades having cooling paths through which a refrigerant flows inside, a plurality of wheels having the aforementioned moving blades in the outer periphery, and at least a spacer member to be installed between the neighboring wheels, a compressor, and a combustor, wherein the spacer member has a plurality of flow paths through which a refrigerant after cooling the moving blades flows and the plurality of flow paths have the first flow paths interconnecting to the cooling paths installed in the moving blades on the first wheel neighboring with the spacer member and interconnecting to the first space formed on the side wall surface with which the second wheel neighboring with the spacer member and the spacer member are in contact and the second flow paths interconnecting to the cooling paths installed in the moving blades on the second wheel and interconnecting to the second space formed on the side wall surface with which the first wheel and the spacer member are in contact, interconnect the first and second spaces and the combustion air flow paths supplied to the combustor to each other, supply compressed air extracted from the compressor to the moving blades cooling paths as a refrigerant so as to cool the moving blades, collect the refrigerant after cooling the moving blades via the first and second flow paths, and use it as combustion air of the combustor.
A refrigerant collection method for gas turbine moving blades according to the present invention is accomplished, in a gas turbine having a turbine rotor which includes a plurality of moving blades having cooling paths through which a refrigerant flows inside, a plurality of wheels having the aforementioned moving blades in the outer periphery, and at least a spacer member installed between the neighboring wheels, by that in the moving blades installed in the first wheel neighboring with the spacer member on the upstream side of gas flow, a refrigerant passing inside is introduced in from the upstream side of gas flow and introduced out on the downstream side of gas flow, and the refrigerant introduced out from the moving blades is introduced out and collected in the first cavity formed in the junction surface of the second wheel neighboring on the downstream side of gas flow of the spacer member and the spacer member via the first flow paths formed in the spacer member and in the moving blades installed in the second wheel, a refrigerant passing inside is introduced in from the downstream side of gas flow and introduced out on the upstream side of gas flow, and the refrigerant introduced out from the moving blades is introduced out and collected in the second cavity formed in the junction surface of the first wheel and the spacer member via the second flow paths formed in the spacer member.